Chemical Reaction between Calcium hydroxide and Chlorhexidine digluconate

Objectives: Calcium hydroxide and chlorhexidine digluconate mixture has been introduced to have more control E. faecalis in the canal. The purpose of the present study was to investigate of chemical reaction between calcium hydroxide and chlorhexidine digluconate solution as used intracanal medicament. Materials and Methods: Calcium hydroxide (Sigma, USA) and either 2% or 20% chlorhexidine digluconate solution (Sigma, USA) were mixed on a mixing slab. Pure calcium hydroxide, dried solid chlorhexidine, and calcium gluconate monohydrate were used as standard reagents. The mixtures were chemically analyzed with X-ray diffractograms, FT-IR, and NMR. X-ray diffractograms were obtained with a Philips X-ray diffractometer (Model: XPert-APD), and FT-IR spectra were obtained with a Bruker EQUINOX 55 spectrometer using a KBr. NMR spectra were recorded on a Varian 500 MHz FT-NMR spectrometer (Model: Unity INOVA. USA) in DMSO-d6. 1 proton FT-NMR, 13-carbon FT-NMR and DEPT-NMR were recorded. Results: The mixture of calcium hydroxide and chlorhexidine digluconate solution showed crystalline structure, amorphous structure and both with the concentration and dose of both reagents. The mixture of calcium hydroxide and chlorhexidine digluconate solution of clinical proportions showed calcium hydroxide crystal, amorphous chlorhexidine base, and amorphous calcium digluconate salt. Deprotonation of NH2+ was evident in chlorhexidine with decrease of hydroxyl ion in calcium hydroxide. P-chloroaminobenzene was not shown in the mixture. Conclusions: Mixing of calcium hydroxide and chlorhexidine digluconate solution produced calcium digluconate salt. After mixing them, positive charged chlorhexidine and hydroxyl ion of calcium hydroxide were decreased and calcium digluconate salt was increased.